It is known for example from US 2006/0191496 A1 to fit a sensor device for conductivity measurement to a heating device for a washing machine or dishwasher. Two sensory areas extend into the water for conductivity measurement and are contacted to the outside in simple manner by electrical terminals.
EP 940494 A1 discloses providing such a sensor device on a tumble dryer. Two electrodes are provided on a sensor module for conductivity measurement with conductance electronics for activation and with an optical coupler for transmitting the signals for evaluation. The conductance electronics is connected to the mains voltage by means of a transformer. In this way it is possible to isolate the sensor module from the remaining equipment via the transformer and optical coupler.
A problem addressed by the present invention is to provide an aforementioned sensor device and a method for operating such a sensor device making it possible to obviate the problems of the prior art and in particular provide a simple practicably usable sensor device which operates reliably.